This invention relates to slip sheets for receiving, handling, storing and shipping a unitized load of product, and, more particularly, to an improved laminated paperboard slip sheet.
In many applications, product, e.g., cartoned or bagged product, is unitized to achieved economies by receiving, shipping, handling and storing the product in bulk loads. For many years, these unitized loads have been carried on conventional hardwood pallets. The wooden pallet system for handling unitized loads was adopted as the most popular system initially because the wood pallet was low in cost, availability of wood was adequate, and it was easy to handle the product on the wooden pallet with a standard and relatively low cost forklift truck. However, the use of wooden pallets has suffered from a number of disadvantages including high initial investment costs, problems in inventoring, storing, and returning the pallets; high handling and transportation costs in shipping pallets in two directions; the fact that wooden pallets consume a high percentage of available hardwood; high cost of pallet maintenance to keep the pallets in service and high cost of pallet replacement; problems of lost pallets; and high weight and volume which adds significant costs to shipment and space requirements for storage of the pallets. Wooden pallets can also cause damage to the load during handling and storage, for example, by nails and broken boards rupturing packages mounted on the pallets and product overhang and load settling into broken areas deforming the load. Further, damage can also result to the top of the load when another wooden pallet is placed on top of it.
Because of these and a number of other disadvantages of wooden pallets, the slip sheet method of handling unitized loads was adopted in the mid-1950's, and its use has continued to expand up to today. A slip sheet is a thin sheet of material, typically a solid fiber, which is of a length and width generally the size of the unit load. The slip sheet has one or more "lips" or "pull tabs" which extend about three to four inches beyond the load allowing the slip sheet to be gripped and pulled onto the platens of a fork truck with the aid of a gripper or push-pull attachment mounted to the fork truck. Typically, the slip sheets are provided with lips or pull tabs on two adjacent sides allowing the load to be picked up either from the front or the side for convenience of loading and full utilization of trailer width, although they can be made with up to four lips or tabs.
Solid fiber is the most commonly used material for slip sheets. Fiber slip sheets have been constructed by laminating three or more sheets of kraft paper together with a waterproof adhesive. The thickness of the sheets typically varies from 0.036 to 0.090 inch. This is typically accomplished by varying the thickness of the individual kraft sheets which make up the lamination. Heavier gauge fiber slip sheets are also available.
The use of slip sheets has contributed significant economies over the use of wooden pallets. Their cost is approximately 1/10th that of a hardwood pallet; and, since they are expendable, they do not require any maintenance, inventory or return. They can be thrown away at the end of the first trip or, if desired, reused until worn out. Moreover, the loss of slip sheets is not a problem. Because they take up essentially no room, slip sheets allow more space in the trailer for the product being shipped. Moreover, since you are shipping relatively lightweight paper instead of heavy hardwood, the weight reduction achieved by using slip sheets instead of wooden pallets creates about a twenty-fold savings of freight weight. Still further, the same number of slip sheets can be stored in about 20% of the space required for wood.